The present invention relates to a method and apparatus for coordinating, in time and space, the process sequence of field desorption ionization.
Ionization by means of electric field desorption is practiced in the field of mass spectrometrie, particularly for ionizing thermo-instable substances which are not very volatile. The known method in this regard is very time-consuming and requires extensive intervention and manipulation by operating personnel.
The known method requires preparation of electrodes, setting up the field. This preparation involves chemical activation for the growth of dendrites in a special apparatus, a process which requires at least ten minutes, but possibly also several hours, depending upon process particulars. Following this activation, the field electrode has to be taken out of the special activating device, for being loaded with the material to be investigated and analyzed. Next, the loaded electrode has to be inserted into a source of ions, including a high vacuum chamber. The test is conducted in that chamber. Subsequently, the electrode has to be removed from this test chamber; and after thorough cleaning, the electrode may be recycled and used anew.
It can readily be seen that this field desorption ionization method involves a rather long measuring cycle, beginning with electrode activation and ending with the cleaning. Many steps and manipulations are required to be carried out by human operators; and as such, this method is not amenable to complete automation.
Also, it is not feasible to couple devices involved in the process directly to sources furnishing the material to be analyzed. Such sources may operate on an intermittent basis, e.g., a fraction collector, or continuously, such as a high-pressure liquid chromatograph.